James Webb Space Telescope Captures Exoplanet Slowly Breaking Apart in Real Time

New Delhi | December 13, 2025 In a rare and groundbreaking observation, scientists using the James Webb Space Telescope (JWST) have watched a distant planet lose its atmosphere in real time, offering an unprecedented look at how extreme space environments can slowly destroy entire worlds. The planet, known as WASP-121b, is a giant gas planet located outside our solar system and is being torn apart by the intense heat and radiation from its parent star. The discovery was made by an international research team led by Romain Allart from the Trottier Institute for Research on Exoplanets in Canada. The findings were published this month in the scientific journal Nature Communications. Researchers used the James Webb Space Telescope along with Canada’s Near Infrared Imager and Slitless Spectrograph, or NIRISS, to carry out the detailed study. WASP-121b belongs to a category of planets known as “ultra-hot Jupiters.” These are massive gas planets that orbit extremely close to their stars. In the case of WASP-121b, one full orbit takes just about 30 hours. Because of this close distance, the planet is constantly exposed to powerful radiation that heats its atmosphere to thousands of degrees. Under such extreme conditions, lighter gases like hydrogen and helium cannot stay bound to the planet. Instead, they escape into space. Scientists observed this atmospheric loss forming two enormous helium tails that trail the planet as it moves around its star. Together, these tails stretch more than 100 times the diameter of the planet and cover nearly 60 per cent of its orbital path. What makes this observation special is the length and detail of the study. In the past, scientists could only observe brief moments of atmospheric escape when a planet passed in front of its star. This time, thanks to the sensitivity of JWST and the precision of the NIRISS instrument, the team monitored WASP-121b continuously for nearly 37 hours. This allowed them to track more than one full orbit and capture the longest and most complete record of helium loss from an exoplanet so far. The data revealed two distinct gas streams. One tail trails behind the planet, pushed by stellar winds and radiation, while the other stretches ahead, pulled by the star’s gravity. This double-tail structure surprised scientists and suggests that the interaction between a planet and its star is far more complex than earlier models predicted. “This discovery shows how dynamic and violent these distant worlds can be,” said lead researcher Romain Allart. He explained that such observations help scientists better understand how planetary atmospheres evolve and how stars influence the fate of nearby planets. The findings also raise important questions about planetary evolution. Over time, continuous atmospheric loss could cause a large gas planet to shrink or even lose its gaseous layer completely. Scientists believe this process may explain why smaller gas planets, known as hot Neptunes, are rare. They could be the remains of much larger planets that were stripped down by their stars. Canada’s NIRISS instrument played a key role in making the discovery possible. According to co-author Louis-Philippe Coulombe, the continuous and precise data provided by NIRISS allowed researchers to study not just atmospheric escape, but also other features such as the planet’s composition, climate, and energy balance. This observation marks a major step forward in exoplanet research. By watching a planet change in real time, scientists are gaining valuable insights into how worlds form, evolve, and sometimes meet their end. As JWST continues its mission, researchers expect even more discoveries that will deepen our understanding of planets far beyond our solar system. James Webb Space Telescope Captures Exoplanet Slowly Breaking Apart in Real Time The James Webb Space Telescope has given scientists a front-row seat to a rare cosmic event — a distant planet slowly losing its atmosphere under extreme heat. Researchers have observed exoplanet WASP-121b being stripped apart in real time, offering one of the clearest views yet of how harsh space conditions can change a planet forever. WASP-121b is an ultra-hot gas giant located far beyond our solar system. It orbits its parent star so closely that one full revolution takes only about 30 hours. Because of this tight orbit, the planet is exposed to intense radiation that heats its atmosphere to thousands of degrees. Under such conditions, light gases like hydrogen and helium escape into space. Using the James Webb Space Telescope along with Canada’s NIRISS instrument, scientists tracked this atmospheric loss in unmatched detail. For nearly 37 continuous hours, the team observed the planet across more than one full orbit. This allowed them to see not just brief snapshots, but the entire process as it unfolded. The observations revealed something unexpected. WASP-121b has two massive helium tails stretching behind and ahead of the planet. One tail is pushed back by powerful stellar winds and radiation, while the other is pulled forward by the star’s gravity. Together, these glowing gas streams extend more than 100 times the planet’s diameter and cover nearly 60 per cent of its orbit. The study was led by researcher Romain Allart from the Trottier Institute for Research on Exoplanets and has been published in Nature Communications. Scientists say this double-tail structure shows that interactions between planets and stars are more complex than earlier models suggested. Over time, this steady loss of atmosphere could dramatically change the planet’s size and structure. Researchers believe such processes may explain why some smaller gas planets are rare — they could be the remains of larger planets that were slowly stripped down by their stars. With tools like JWST, scientists are now watching planets evolve in real time, opening a new chapter in our understanding of distant worlds.